Hyperthreading is a risk factor for spectre/meltdown
and other attacks.
Disabling it is a best practise. Those who need it
can always turn this option back on. Otherwise, disabling
it by default is a simply courtesy to the average user,
in the interest of security.
Signed-off-by: Leah Rowe <leah@libreboot.org>
The Libreboot 20241206 release provided FSP pre-assembled
and inserted into the ROM images; the only file inserted
by vendor.sh was the Intel ME.
Direct distribution of an unmodified FSP image is permitted
by Intel, provided that the license notice is given among
other requirements. Due to how coreboot works, it must split
up the FSP into subcomponents, and adjust certain pointers
within the -M component (for raminit).
Such build-time modifications are perfectly fine in a coreboot
context, where it is expected that you are building from source.
The end result is simply what you use.
In a distribution such as Libreboot, where we provide pre-built
images, this becomes problematic. It's a technicality of the
license, and it seems that Intel themselves probably intended
for Libreboot to use the FSP this way anyway, since it is they
who seem to be the author of SplitFspBin.py, which is the
utility that coreboot uses for splitting up the FSP image.
Due to the technicality of the licensing, the FSP shall now
be scrubbed from releases, and re-inserted.
Coreboot was inserting the -S component with LZ4 compression,
which is bad news for ./mk inject beacuse the act of compression
is currently not reproducible. Therefore, coreboot has been
modified not to compress this section, and the inject command
doesn't compress it either. This means that the S file is using
about 180KB in flash, instead of about 140KB. This is totally OK.
The _fsp targets are retained, but set to release=n, because these
targets *still* don't scrub fsp.bin; if released, they would
include fsp files, so they've been set to release=n. These can
be used on older Libreboot release archives, for compatibility.
The new ROM images released for the affected machines are:
t480_vfsp_16mb
t480s_vfsp_16mb
dell3050micro_vfsp_16mb
Note the use of _vfsp instead of _fsp. These images are released,
unlike _fsp, and they lack fspm/fsps in the image. FSP S/M must
be inserted using ./mk inject.
This has been tested and confirmed to boot just fine.
The 20241206 images will be re-compiled and re-uploaded with this
and other recent changes, to make Libreboot 20241206 rev8.
Signed-off-by: Leah Rowe <leah@libreboot.org>
Leah Rowe